Update: The photo, Larry West says, is real! Quoth:
The photo is 100% real. I originally uploaded it using my phone, and wound up just adding my watermark real quick.
The story behind it is simple: I was walking around Center City when I started hearing police sirens around 10:30 last night. All of a sudden, a man wearing all black with white hair ran by me so fast I wasn’t able to get a good look. I look up, saw the signal, and knew what had happened. They had lit the William Penn signal to bring peace and Quakerhood back to Philadelphia!
This sounds utterly insane, but hey, who knows! Either way, the legend of the Billy Penn Signal is born!
This image of what shall now forever be called "The Bill Penn Signal" popped up on Reddit. It's credited to local photog/designer Larry West, but it's unclear if he doctored it or not. (I contacted him and am waiting for comment.) Either way, let us agree that it is awesome.